The present invention relates to a support for photographic paper and more particularly, to a polyolefincoated paper for photograph having a finely embossed surface.
Photographic papers include specular type, i.e., those having a smooth and gloss surface and embossed type. The embossed type photographic papers have a finely embossed surface, a matte surface, a silk surface, a cloth surface or the like. Such embossed type photographic papers have the merits that fingerprints are hardly left thereon as compared with on the specular type photographic papers having a smooth surface, they are superior in handling properties (i.e. they can be easily handled because they hardly adhere to each other when piled up) and a sharp image can be obtained owing to their low gloss. Recently, water-resisting supports comprising a paper coated with a polyolefin resin on both sides have been generally used for the purpose of rapid development and these are made by a coating method called melt extrusion method which comprises coating a molten polyolefin resin on both sides of a paper and then cooling the paper.
The embossed type photographic paper is made by using a cooling roll subjected to the desired embossing which is used in the melt extrusion method.
It is needless to say that configuration of the finely embossed surface has an important influence on quality and cost of photographic papers. The configuration determines not only the gloss of photographic papers, but also the maximum speed of coating an emulsion on a support. The present invention provides a support which not only can give a proper gloss as a finely embossed type photographic paper and can stand high-speed coating of an emulsion but also has good handling properties.
The emulsion is coated on a photographic support by an E bar method by which multiple layers are simultaneously coated or a curtain coating method. Especially, in the case of a color photographic paper, 3-8 emulsion layers are simultaneously coated and the total thickness of the emulsion layers is thin, namely, 10-20 .mu.m. In view of productivity and cost, high speed coating is strongly demanded, but there is the problem that shifting of emulsion layer occurs at the time of high speed coating for some configuration of the embossed surface.
It has been found that the shifting of emulsion layers from each other occurs due to the air involved between the emulsion layers for some configuration of the surface of the support when the emulsion layers are coated on the surface of the support.